Microstructure and Electrical Properties of Doped ZnO Varistor Nanomaterials

2004 ◽  
Vol 99-100 ◽  
pp. 127-132 ◽  
Author(s):  
Xueya Kang ◽  
Tu Minjing ◽  
Ming Zhang ◽  
Wang Tiandiao
Keyword(s):  
Electrical Properties ◽  
Sol Gel ◽  
Nonlinear Coefficient ◽  
Varistor Ceramic ◽  
Homogeneous Microstructure ◽  
Grain Sizes ◽  
Zno Varistor ◽  
Nanometer Materials ◽  
Doped Zno ◽  
Tan Δ

A sol-gel method of preparation doped ZnO varistor nanomaterials is described, The influences of doped ZnO nanomaterials for varistor microstructure and electrical properties (nonlinear coefficient α, breakdown voltage V1mA , dielectric constant ε, and dielectric loss tan δ) are investigated. Compared with the conventional mixed oxide technique, varistor ceramic of prepared by nanometer materials showed a more homogeneous microstructure, smaller grain sizes, higher densities and excellent electrical properties.

scholarly journals Dielectric and varistor properties of rare-earth-doped ZnO and CaCu3Ti4O12 composite ceramics

2013 ◽  
Vol 03 (01) ◽  
pp. 1350001 ◽  
Author(s):  
Huafei Lu ◽  
Yuanhua Lin ◽  
Jiancong Yuan ◽  
Cewen Nan ◽  
Kexin Chen
Keyword(s):  
Rare Earth ◽  
Sol Gel ◽  
Nonlinear Coefficient ◽  
Composite Ceramic ◽  
Dielectric Behavior ◽  
Composite Ceramics ◽  
High Dielectric Permittivity ◽  
Doped Zno ◽  
Co Precipitation ◽  
High Dielectric

To investigate the multi-functional ceramics with both high permittivity and large nonlinear coefficient, we have prepared rare-earth Tb -and- Co doped ZnO and TiO 2-rich CaCu3Ti4O12 (TCCTO) powders by chemical co-precipitation and sol–gel methods respectively, and then obtained the TCCTO/ ZnO composite ceramics, sintered at 1100°C for 3 h in air. Analyzing the composite ceramics of the microstructure and phase composition indicated that the composite ceramics were composed of the main phases of ZnO and CaCu3Ti4O12 (CCTO). Our results revealed that the TCCTO/ ZnO composite ceramics showed both high dielectric and good nonlinear electrical behaviors. The composite ceramic of TCCTO: ZnO = 0.3 exhibited a high dielectric constant of ~210(1 kHz) with a nonlinear coefficient of ~11. The dielectric behavior of TCCTO/ ZnO composite could be explained by the mixture rule. With the high dielectric permittivity and tunable varistor behaviors, the composite ceramics has a potential application for the higher voltage transportation devices.

Influence of CeO2-Doping on the Electrical Properties of ZnO-Bi2O3-Based Varistor Ceramics

2016 ◽  
Vol 697 ◽  
pp. 262-266
Author(s):  
Zhan Chuan Cao ◽  
Liao Ying Zheng ◽  
Li Hong Cheng ◽  
Tian Tian ◽  
Guo Rong Li
Keyword(s):  
Grain Size ◽  
Phase Composition ◽  
Detection Limit ◽  
Electrical Properties ◽  
Barrier Height ◽  
Nonlinear Coefficient ◽  
Donor Concentration ◽  
Average Grain Size ◽  
Doped Zno ◽  
Density Of Interface States

The microstructure and electrical properties of CeO2-doped ZnO-Bi2O3-based varistors were investigated for different amounts of the dopant. The phase composition of CeO2-doped samples was similar to the undoped samples. Ce mainly segregated at the grain boundaries within the EDS detection limit. The average grain size decreased from 7.3 to 6.7 μm and the breakdown voltage increased from 438 to 501 V/mm when the content of CeO2 ranged from 0 to 0.2 mol%. The nonlinear coefficient increased from 38 to 51 when the content of CeO2 increased from 0 to 0.1 mol%., but the further doping caused it to decrease up to 44 at 0.2mol%. The leakage current decreased from 1 to 0.4 μA/cm2 when the content of CeO2 ranged from 0 to 0.1 mol%. Then it increased to 0.7 μA/cm2 at 0.2 mol%. The density of interface states, the barrier height and the donor concentration increased when the content of CeO2 ranged from 0 to 0.1 mol%, but decreased at 0.2 mol%. Hence, when the content ranges from 0 to 0.1 mol%, CeO2 acts as a donor and can improve the electrical properties.

Structural and Electrical Properties of (Cu, Co) Co-Doped ZnO Thin Film

2013 ◽  
Vol 774-776 ◽  
pp. 964-967
Author(s):  
Ping Cao ◽  
Yue Bai
Keyword(s):  
Electrical Properties ◽  
Sol Gel ◽  
Hall Effect Measurement ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Co Doping ◽  
Structural And Electrical Properties ◽  
Doped Zno ◽  
Cu Ions ◽  
Co Doped

Successful synthesis of Cu, Co co-doped ZnO film is obtained by sol-gel method. The structural and electrical properties of the sample were investigated. X-ray diffraction spectroscopy analyses indicate that the Co and Cu co-doping can not disturb the structure of ZnO. No additional peaks are observed in the Zn0.99Co0.01CuxO and Cu+ and Co2+ substitute for Zn2+ without changing the wurtzite structure. By Hall-effect measurement p-type conductivity was observed for the Cu co-doped film. XPS result confirmed Cu ions are univalent in the films.

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